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PubMed1981

Effect of diabetes, insulin, starvation, and refeeding on the level of rat hepatic fructose 2,6-bisphosphate.

The influence of alloxan diabetes and starvation for 72 h on the level of rat hepatic fructose 2,6-biphosphate was investigated. Both diabetes and starvation decreased the level to 10% of the value found in livers of normal, fed rats (10 nmol/g liver). The activity of the enzyme responsible for the synthesis of fructose 2,6-bisphosphate, 6-phosphofructo 2-kinase, was also decreased in livers of diabetic rats. Insulin administration for 24 h to diabetic rats restored the level of fructose 2,6-bisphosphate to normal. Refeeding a high carbohydrate diet for 24 h to starved rats resulted in fructose, 2,6-biphosphate levels that were 2.5-fold higher than that in livers of fed rats. The level of fructose 2,6-bisphosphate in diabetes and starvation, and after refeeding correlates as well with the rate of glycolysis and gluconeogenesis in these states and thereby provides further support for its role in regulating hepatic carbohydrate metabolism.

Animals↗
PubMed1987

Protein sparing in skeletal muscle during prolonged starvation. Dependence on lipid fuel availability.

Previous studies indicated that protein sparing in skeletal muscle during prolonged starvation depends on the availability of lipid fuels. To test this relationship further, fasted rats conserving protein were treated in vivo for 6-8 h with the antilipolytic agent nicotinic acid (NA) or with tetradecylglycidate (TDGD), an inhibitor of long-chain fatty acid oxidation. After treatment, protein synthesis and degradation in skeletal muscle were evaluated with the perfused rat hindquarter. NA treatment decreased plasma 3-hydroxybutyrate and free fatty acids and increased plasma urea and urine urea excretion, indicating increased breakdown of body protein. TDGD produced similar metabolic effects, except that plasma free fatty acids were markedly increased as a result of inhibition of fatty acid oxidation. NA and TDGD also decreased plasma insulin and increased plasma corticosteroid. Inhibition of lipid metabolism in vivo resulted in accelerated loss of protein from skeletal muscle due to decreased protein synthesis and increased protein breakdown. NA increased both total (i.e., tyrosine release) and myofibrillar (i.e., 3-methylhistidine release) protein breakdown, whereas TDGD increased the breakdown of only nonmyofibrillar proteins (i.e., 3-methylhistidine release by perfused hindquarter was not altered). These data indicate that lipid fuels may directly modulate protein metabolism in muscle during prolonged starvation and may prevent a rise in catabolic hormones. They also indicate that free fatty acids may directly attenuate the breakdown of myofibrillar proteins in muscle during prolonged starvation and that this may be unrelated to their oxidation.

3-Hydroxybutyric Acid↗
PubMed1981

Effects of maternal starvation on some blood metabolites, liver glycogen, birth weight and survival of piglets.

Pregnant crossbred sows were assigned to three treatments during the third trimester of gestation for an evaluation of the effects of maternal starvation on fetal development and piglet survival. Two groups of sows were taken off feed (water and trace mineralized salt only) on days 93 and 107 of gestation, respectively; the third group was fed 1.82 kg of complete sow diet/day and served as the control. Litter size, gestation length and pig birth weight in the 7-day and 21-day starvation groups were not different from those in the control group (P less than .05). Liver weight was depressed (P greater than .05) among the 7-day and 21-day progeny. However, liver glycogen concentrations and total liver glycogen were unaffected. Maternal blood glucose decreased to a fasting but steady level, while free fatty acid (FFA) increased in the two starved groups. Blood glucose and FFA at birth were similar for all treatment groups; however, FFA increased in the progeny of sows in the 7-day (P greater than .05) and 21-day (P greater than .01) starvation groups at 48 hr of age. Blood glucose at 48 hr did not vary (P less than .05), but the control progeny showed a faster glucose utilization, suggesting a greater dependence on carbohydrate metabolism than in the progeny of starved dams. Survival rate at 72 hr of age was higher among 21-day (43.8%) and 7-day (37.5%) progeny than among control progeny (8.5%). The increased plasma FFA level observed with fasting in the progeny of starved dams might indicate a shift toward lipid metabolism, which would account for the improved survival observed among the progeny of treated dams.

Animals↗
PubMed2006

Adaptive cellular mechanisms in response to glutamine-starvation.

Glutamine (Gln) utilising cells suffer from Gln-starvation during critical illness when plasma Gln levels are decreased. This study investigates whether such cells activate adaptive mechanisms. Monocytic U937 cells were cultured at 0.6 and 0.2 mM Gln for up to four days. Within the first day a decrease of ATP (78% of control), intracellular free Gln (13%), Hsp70 (74%) and proliferation rate (79%) was observed. A prolonged culture at 0.6 mM Gln for additional three days led to a recovery of ATP (97%), Hsp70 (91%) and proliferation (92%). The intracellular free Gln increased only to 41%. At 0.2 mM Gln, however, all levels remained decreased. The activation of the metabolic sensor AMP activated kinase (AMPK) increased immediately in Gln-starving cells but regained normal values only in cells cultured at 0.6 mM. A proteomic analysis identified 23 proteins, which were affected by Gln starvation including metabolic enzymes, proteins involved in synthesis and degradation of RNA and proteins, and stress proteins. These data show that Gln-utilising cells activate adaptive mechanisms in response to Gln-starvation, which enable them to overcome a Gln shortage. At very low Gln concentrations, these adaptive mechanisms are not sufficient to countervail the lack of the amino acid.

Adaptation, Physiological↗
PubMedDate not supplied

Effect of short-term starvation on Leydig cell function in adult rats.

An experiment was carried out to analyze the effect of 3 days of starvation on the Leydig cell function in adult rats. Starvation markedly decreased plasma insulin and testosterone levels (p < .05). The weight of testes was maintained, whereas the testicular interstitial fluid volume decreased (p < .05). The level of testosterone decreased in this fluid (60%), whereas insulin levels showed no significant change. Purified Leydig cells showed normal LH/hCG binding in fasted rats but low insulin binding. The ability of these cells to produce testosterone in vitro was normal under both basal conditions and hCG stimulation in the absence and presence of insulin in the incubation medium. These data suggest that there is no gross impediment in the Leydig cell capacity to produce testosterone that might explain the starvation-associated decrease in plasma testosterone.

Animals↗
PubMed1976

Glucocorticoid and starvation effect on glycosaminoglycans in vascular connective tissue. Biochemical studies on repair processes in rabbit aorta.

Male rabbits were injured by a single mechanical dilatation injury of aorta and then injected with prednisone 2 mg/kg or saline for 14 days or subjected to starvation. The biosynthesis of the sulfated glycosaminoglycans as evaluated by the uptake of 35S-sulfate and the content of the glycosaminoglycans were measured on the intima-media layer of the descending thoracic aorta. The results indicate that prednisone may inhibit the biosynthesis of heparan and/or dermatan sulfate while starvation increases the biosynthesis of all the sulfated glycosaminoglycans. No alterations were observed in the total amount of glycosaminoglycans in aorta following glucocorticoid injection or starvation. The metabolism of aortic glycosaminoglycans during repair is less sensitive to the action of prednisone than in undamaged aorta. This contrasts with the effect of prednisone on the metabolism of aortic collagen.

Animals↗
PubMed1983

Distribution of amino acids and amino-acid enzymes in whole kidney and renal cortex. Effect of 24-h starvation.

The levels of activity of amino-acid enzymes (alanine-, aspartate- and tyrosine transaminases, serine dehydratase, glutamate dehydrogenase, glutamine synthetase, arginase and adenylate deaminase) in the kidney cortex and whole kidney of control and 24-h starved adult rats have been determined from crude homogenates. The individual amino-acid content of the two kidney fractions indicated has also been studied. Serine dehydratase was found mainly in the cortex, whilst glutamine synthetase presence was mainly limited to the medulla. The distribution of adenylate deaminase and glutamate dehydrogenase is remarkably uniform along the kidney. Starvation induced decreases in arginase and adenylate deaminase activities as well as a decrease in cortical serine dehydratase. Analysis of the variance of the enzyme data showed no significant overall changes with respect to distribution and starvation. The same analysis applied to aminograms indicated only significant changes when the distribution was studied on starved samples as a whole, with changes mainly in the urea cycle and some essential amino acids. The results suggested a remarkable degree of uniformity in kidney composition both with respect to amino acid and enzyme distribution. This uniformity is not markedly affected by starvation despite the important rôle of kidney in the overall amino-acid economy of the Mammal.

AMP Deaminase↗
PubMed1989

Metabolic response to short term starvation in non-pregnant and late pregnant cafeteria-obese rats.

We have determined the blood metabolite responses to a 24-h starvation period of cafeteria obese rats, in both non-pregnant and late pregnant states. In the fed condition the concentrations of glucose, lactate, pyruvate, glycerol and urea do not differ when compared in control and obese rats, but acetoacetate and 3-hydroxybutyrate levels are higher in the obese group. The overall response of the cafeteria-obese rats to starving seems characterized by decreased rates of glucose and amino-acids utilization, substituted by a more intense utilization of lipid fuels, with excess ketone bodies production and increased utilization of the mobilized glycerol. What we observed in the obese pregnant response to starvation can be summarized as the additional or superimposed effects of excess fat reserves. In the obese pregnant starved rats a less severe hypoglycaemia, lower levels of glycerol (as a consequence of increased utilization), reduced urea levels, and increased acetoacetate and 3-hydroxybutyrate levels were observed. It can be assumed that the pregnant obese rat response to starvation is related to the size of the fat deposits: the more obese, the more hyperketonaemia and less hypoglycaemia, and even diminished rates of amino-acid utilization, as indicated by a lower levels, when compared to the lean pregnant.

3-Hydroxybutyric Acid↗
PubMedDate not supplied

Effect of starvation on the in vivo intestinal absorption of sugars and amino acids in young chickens (Gallus domesticus).

The effect of different patterns of starvation (acute and intermittent) on the in vivo intestinal absorption of glucose and tryptophan during the first days of Gallus domesticus chicks life was measured. Both acute and intermittent starvation increase duodenal absorption of glucose and jejunal absorption of tryptophan. Intermittent starvation tends to reduce the effect of age which normally decreases intestinal uptake of nutrients. This effect is clearer for glucose absorption than for tryptophan absorption.

Animals↗
PubMed2003

Induced expression of the heat shock protein genes uspA and grpE during starvation at low temperatures and their influence on thermal resistance of Escherichia coli O157:H7.

Heat shock proteins play an important role in protecting bacterial cells against several stresses, including starvation. In this study, the promoters for two genes encoding heat shock proteins involved in many stress responses, UspA and GrpE, were fused with the green fluorescent protein (gfp) gene. Thus, the expression of the two genes could be quantified by measuring the fluorescence emitted by the cells under different environmental conditions. The heat resistance levels of starved and nonstarved cells during storage at 5, 10, and 37 degrees C were compared with the levels of expression of the uspA and grpE genes. D52-values (times required for decimal reductions in count at 52 degrees C) increased by 11.5, 14.6, and 18.5 min when cells were starved for 3 h at 37 degrees C, for 24 h at 10 degrees C, and for 2 days at 5 degrees C, respectively. In all cases, these increases were significant (P < 0.01), indicating that the stress imposed by starvation altered the ability of E. coli O157:H7 to survive subsequent heat treatments. Thermal tolerance was correlative with the induction of UspA and GrpE. At 5 degrees C, the change in the thermal tolerance of the pathogen was positively linked to the induced expression of the grpE gene but negatively related to the expression of the uspA gene. The results obtained in this study indicate that UspA plays an important role in starvation-induced thermal tolerance at 37 degrees C but that GrpE may be more involved in regulating this response at lower temperatures. An improvement in our understanding of the molecular mechanisms involved in these cross-protection responses may make it possible to devise strategies to limit their effects.

Adaptation, Physiological↗
PubMed1976

[Age characteristics of acid-base equilibrium and the blood coagulation system in starvation].

The state of the acid-base balance and of the blood coagulation system was studied in starvation of young (5-6-month-old) and old (24-26-month-old) male rats during starvation. The periods of the maximal changes coincided in both systems; in the young animals the onset of the acidotic crisis and hypercoagulation development occurred earliear and were more pronounced. Old animals proved to be more resistant to the conditions of starvation and died later than the young ones.

Acid-Base Equilibrium↗
PubMedDate not supplied

Starvation-induced pathobiology in the gut of carp (Cyprinus carpio L.).

In order to assess the effects of starvation on intestinal intraepithelial lymphocytes (i-IEL) count and histological changes of the carp gut mucosa, one group of fish (n = 10) were fed commercially prepared standard diets and another group of fish (n = 10) were starved for 4 weeks. Carp starved for 4 weeks developed enteropathy, comprising folds atrophy, stratum compactum hyperplasia, significant periodic-acid-Schiff (PAS)-positive (P < 0.00001), but not Alcian blue (ALB)-positive, goblet cell (GC) hyperplasia and a significant decrease (P < 0.00001) in i-IEL numbers. These changes were associated with a dense cellular infiltrate into the lamina propria. Taken together, these data suggest that the pathobiology of starvation-induced i-IELs decrease, matching PAS-positive goblet cell proliferation and inflammatory cells homing to the gut, could be classified as a non-infectious enteropathy induced by starvation.

Animals↗
PubMed2000

[Predation on Myzus persicae by Propylaea japonica adults with different extents of starvation].

The study showed that the functional response of predation on M. persicae by the female and male adults of P. japonica with different extents of starvation belonged to the type of Holling II. Female adults had a larger attacking rate than male adults, but the predacious amount of M. persicae by female and male adult predators of different extent of starvation within 24 hrs had no significant difference. The predacious amount by female adult was larger than that of male. The significant difference of predacious amount between female and male adults increased with the time of their starvation and the prey density. The predation by unstarved female and male adult predators on M. persicae in 24 hours was concentrated at 6:00-18:00 and the predation rate (V) between female and male adults had no significant difference. The predation by starved female and male adults for 48 h on the prey in 24 hours was at 0-4 hours after the experiment started, and the predation rate(V) between female and male starved adults had no significant difference either.

Animals↗
PubMed1992

Renal sodium conservation during starvation in rats.

The natriuresis of fasting has been well characterized in man and rabbits but not in rats. The daily effects of fasting on glomerular filtration rate (GFR) and urinary sodium and potassium excretion were evaluated in Munich-Wistar rats (260-310 g) submitted to prolonged starvation (2-8 days). Rats do not present the natriuresis of fasting. Sodium excretion was reduced since the first few hours (0-4 h) of starvation. Antinatriuresis was abrupt during the early periods (1st and 2nd days) and stabilized at very low levels. During the early phase (4 days), sodium retention occurred due to both reduced glomerular filtration and increased tubular reabsorption. However, during the late phase (after the 4th day), antinatriuresis was mainly induced by the elevation in tubular reabsorption, since a normalization of GFR was observed. Thus, these homeostatic mechanisms permit adequate renal sodium conservation during starvation in rats.

Animals↗
PubMed1992

Water proton ion in leg muscles of crayfish subjected to starvation.

1. Using nuclear magnetic resonance, we studied the relationships of in vivo water to establish the correlation between the degree of starvation and the spin-lattice or spin-spin relaxation times (T1 and T2, respectively) of water protons in the leg muscles of crayfish (Procambarus clarkii). 2. As the period of starvation increased, the water content as a component of body weight increased, and the T1 value was proportional to the increase in water content of the leg muscles of the crayfish. 3. The T2 value increased exponentially in comparison with the T1 value for each corresponding stage. 4. Our studies suggest that the state of the body water resulting from starvation was affected by cellular environmental change.

Animals↗
PubMed1992

Changes in body composition of germ-free and conventional chickens during starvation.

1. Changes in body composition during starvation were compared between germ-free (GF) and conventionalized (CVL) chicks in experiment 1. At 8 days of age, the GF birds were divided into two groups, i.e. GF and CVL groups. The CVL birds were inoculated with faeces from conventionally reared birds. Until 14 days of age, both birds were fed a diet ad lib. and thereafter starved for 6 days. 2. Nitrogen loss during starvation was significantly lower in CVL birds, though the reverse was true for water loss. Fasting heat production was comparable between two environments. 3. Influence of the gut microflora on body weight and nitrogen losses during starvation was investigated in birds prefed diets high or low in dietary protein in experiment 2. 4. No significant effect of the gut microflora was observed in body weight and nitrogen losses. Body weight was severely reduced in birds prefed the high protein diet and nitrogen loss was lower in birds prefed the low protein diet.

Animals↗
PubMed2004

[Research advances in ecophysiological effects of starvation on crustacean].

As a major environmental stress, starvation greatly and extensively affects crustacean in ecophysiological aspects. In this paper, the existing information on the ecophysiological responses of crustacean to starvation, including development and survival, metabolism, digestive gland and enzyme, body composition, and recovery growth was summarized, and on the basis of these, the future research directions, i. e., the compensatory growth and its mechanism, and the relationship between starvation and immunocompetence, were proposed.

Animals↗
PubMed1991

Effects of starvation on the tissular lipogenic rate in the obese Zucker rat.

The lipogenic rate of the obese rats was significantly higher than that of the lean rats in liver, white adipose tissue, skeletal muscle, heart and carcass. In the lean rats, a 24 h starvation period caused a significant decrease in the lipogenic rate of white adipose tissue and skeletal muscle while it increased that of heart, brain and brown adipose tissue. In the obese rats, starvation decreased the lipogenic rate in liver, skeletal muscle, white adipose tissue, brown adipose tissue and carcass. In spite of this, liver and skeletal muscle showed higher rates of lipid synthesis than the corresponding fed lean. It is concluded that starvation induces a qualitatively similar response in the obese versus the lean rat although the total lipogenic capacity of the animal is still higher.

Adipose Tissue↗